EPA Mercury Study

On Friday, December 19th EPA Administrator, Carol Browner, approved the release of the Agency's long-awaited Mercury Study Report to Congress. The Mercury Study Report is mandated by Section 112(n)(1)(B) of the Clean Air Act and was originally scheduled for completion in November 1994. The Report to Congress is an eight volume document, and currently, the Executive Summary (approximately 100 pages) is available on our FTP Library for your download. Also available is a 4- page Overview that summarizes the study. The remaining seven volumes of the report are scheduled to be posted on the Internet by EPA during January 1998. Below, we summarize some of the key findings presented in the Overview of the report.

EMISSIONS: Annual anthropogenic mercury emissions in the U.S. are about 158 tons, and the majority (87%) are attributed to combustion sources. Of the 158 tons, EPA attributes about 52 tons (33%) to coal-fired utility boilers. However, total annual global emissions of mercury (including natural sources) are estimated to be 5,500 tons. Based on this estimate, all U.S. emissions are no more than 3 percent of total, global emissions.
HEALTH IMPACTS: EPA extrapolated from high-dose exposures that occurred during the Iraq grain incident to derive a RfD for methylmercury. The RfD (reference dose) is the level at which lifetime exposures are expected to be safe. Because of safety factors incorporated in an RfD, exposures above the RfD are not necessarily hazardous, but risk are expected to increase as exposures to methylmercury increase. Because of the uncertainties associated with extrapolating high-dose exposures to low - level environmental exposures, EPA and other Federal agencies intend to participate in an interagency review of human data on methylmercury, including the most recent studies from the Seychelle Islands and the Faroe slands. The purposes of this review are to examine the robustness of EPA's RfD and to obtain a consensus on safe levels of mercury exposures among the various Federal agencies.
MERCURY CONTROL TECHNOLOGIES: EPA states that the largest remaining source of mercury emissions are coal-fired utility boilers. Because the chemical species of mercury emitted vary from plant to plant, there is no single control technology that effectively removes all forms of mercury. There remains a wide variation in the estimate cost of mercury control for utility boilers and the possible impact of such cost on consumers. Preliminary cost estimates for utility boilers are in the billions of dollars per year. EPA concludes that cost-effective means to deal with mercury during product life-cycle, rather than just at the point of disposal need to be pursued.

RMB Consulting & Research, Inc.
Last Revised: May 22, 1998